1. Field of the Invention
The invention in general relates to valve supervisory switches, and more particularly to a supervisory switch that is easily adapted to provide effective supervision in a wide variety of valve monitoring situations.
2. Description of the Prior Art
Valve supervisory switches are commonly used to monitor the position of the valves in fire extinguishing sprinkler systems. Two types of supervisory switches are known in the art: a linearly activated (slide) type switch and a swing activated (pivot) type switch. Generally the linearly activated switch is used to monitor the movement of the valve stem in a conventional screw-type valve (see below). Generally the swing activated switch is used to monitor a post indicator valve (see below). It would be highly desirable to have a single supervisory switch that could be easily adapted to either the linearly activated or swing activated configuration. This would not only result in a savings in inventory of two different switches, but also would allow adjustments to be readily made in the field in the case of error or other situations in which a different type of valve is encountered than was anticipated.
The post indicator valve may be either of the flag rising or flag falling variety. Prior art supervisory switches must be inverted to adapt them from the flag rising variety to the flag falling valve variety. This requires that the wiring ductwork be located differently in the two situations. It would be desirable if the valve could be adapted easily for both the flag rising and flag falling variety of valves which would permit the ductwork to be installed the same in both instances.
In addition, fire sprinkler valves vary considerably from one manufacturer or model to the next, and the particular environment of a valve in the field may required different placement of the supervisory valve and/or its associated ductwork and wiring. Thus it would be highly desirable to have a valve that is readily adjustable to a wide variety of field situations.